On 2015-04-22 6:04 AM, Howard Chu wrote:
Brian Reichert wrote:
> On Tue, Apr 21, 2015 at 08:23:31AM -0700, Quanah Gibson-Mount wrote:
>> --On Tuesday, April 21, 2015 11:54 AM -0400 Brian Reichert
>> <reichert(a)numachi.com> wrote:
>>> What does your config file look like?
>>> In particular, what does this setting look like for you:
>>> # Threads - four per CPU
>>> threads 8
>> According to his summary, he's using 48 threads.
> Thanks for pointing that out; I should finish my coffee before
> posting. :)
>> 4 per CPU/core was a good
>> rule of thumb with bdb/hdb. So far in playing with back-mdb, it's
>> closer to 2 per CPU/core for me in benchmarking.
Interesting. What is the
relationship between the number of threads and
the number of concurrent bind operations?
If I have, say, 500 clients wanting access to perform simple
authentication/bind and perform some read/write operation, how is this
usually handled within slapd?
> Useful to note. Has this detail ended up in any docs yet?
No, nor should it. Performance depends on system environment and
workload - the right value is one that each site must discover for
themselves in their own deployment.
Are there any clues about key factors affecting this? Linux, in this
case, has vm.swappiness set to 10, vm.dirty_ratio at 12 and
vm.dirty_background at 3. However I've noticed that when dirty pages are
flushed to disc, the system stalls. And that operation appears to take a
relatively long time. Disc write speed should be close to 130MB/s (file
copy, dd test etc) however it appears to be much slower than this with
the page flush.